Robin Williams' personal assistant and close friend Rebecca Erwin Spencer has paid tribute to the late actor.

Rebecca, who found him dead at his home in California on Monday after he committed suicide, posted the message on her open Facebook profile.

She wrote "What a time we had!" next to a picture of the late actor on one of his United Service Organisation tours, which she made her cover photo on the social network site.

According to Radar Online, Rebecca was seen at the actor's house on Tuesday around 11am for a few minutes before leaving and has also been seen going in and out on other occasions since his death.

They also report that friends had gathered at her and her husband Dan's home following the shock news.

(Photo: Rebecca Erwin Spencer / Facebook)

During a press conference on Tuesday, Lieutenant Keith Boyd of the Marin County coroner’s office said it was his personal assistant who discovered his body at his home in California after his wife thought he was asleep and left the house.

He also said that the Oscar-winning actor, who was sleeping separately from his wife, was last seen by Susan Schneider at 10.30pm on Sunday night as she went to bed at their California home.

It is unknown what time Williams went to bed, if at all, as Lt. Keith Boyd from the Marin County Sheriff's Office would not confirm if the actor was found in a bedroom.

The 63-year-old was discovered after his wife left the house the following morning (August 11) believing that Williams was still asleep.

(Photo: Rebecca Erwin Spencer / Facebook)

It is not clear if a suicide note was found at the scene but a toxicology report will be carried out, with results taking up to six weeks before an official ruling is made.

Following the shock news of her husband's death, Schneider paid a loving tribute to her "husband and my best friend".

She said: “This morning, I lost my husband and my best friend, while the world lost one of its most beloved artists and beautiful human beings.

“I am utterly heartbroken. On behalf of the Robin’s family, we are asking for privacy during our time of profound grief.

(Photo: Getty)

“As he is remembered, it is our hope the focus will not be on Robin’s death, but on the countless moments of joy and laughter he game to millions."

Meanwhile, the Aladdin star's daughter Zelda paid tribute to her father in a touching Instagram post.

The 25-year-old actress shared a quote from Antonie De Saint-Exuprery's novella The Little Prince with her 40, 087 followers.

"You - you alone will have the stars as no one else has them... In one of the stars I shall be living. In one of them I shall be laughing.